#define _CRT_SECURE_NO_WARNINGS
#include<iostream>
using namespace std;
class sigma
{
private:
	int Start;
	int End;
	int a;
	int b;
	int c;
public:
	sigma(int start,int end)
	{
		Start = start;
		End = end;
		a = 2; b = 3; c = 1;
	}
	int calculateSum()const
	{
		int ret = 0;
		for (int i = Start; i <= End; ++i)
		{
			ret += a * i * i + b * i + c;
		}
		return ret;
	}
};
int main()
{
	cout << sigma(1,20).calculateSum() << endl;
	return 0;
}